Do you have a stuffy or blocked nose?
If your nose is blocked, don't try to open it up by vigorously blowing it. Blowing one's nose consists of a deep mouth inhalation and forceful exhalation and leads to a loss of CO2 in lungs, which normally results in the deterioration of health. Instead of blowing, try to unblock your nose with the following technique:
Close your mouth and block your nose with your fingers for a comfortable number of seconds (two to five). While you are not breathing, move your head rapidly up and down. Open your nose and try breathing through it. If you cannot, gently inhale through your slightly opened mouth and repeat the exercise.